Conventionally, in some cases, a mounting member formed with a vibration isolating rubber part is arranged above or below each front side frame, and a power unit and a subframe are supported by the mounting members, where the power unit includes an engine and a transmission and is mounted on the subframe. For example, in the case where the mounting members are arranged below the front side frames, the mounting members are fastened with bolts to nuts arranged on lower walls inside the front side frames, and the subframe is supported by the mounting members.
Meanwhile, Patent Literature 1 discloses an installation structure for a mounting apparatus wherein, when an engine mount is to be arranged above the front side frames, nut members for fixing the engine mount are arranged on upper walls of the front side frames each having a closed cross section, and the nut members are fixed to supporting plates, which extend to form a partition almost dividing the inner spaces of the front side frames. In the structure disclosed in Patent Literature 1, the inclination angles of the above supporting plates with respect to the length direction of the side frames are set such that the positions at which the front side frames are deformed by bending can be optimized.